mymatrix.java

java老师给的java例子很不错

//MyMatrix.java文件
public class MyMatrix 					//矩阵类MyMatrix
{
	private int[][] table;				//矩阵元素表
  	private int height; 				//矩阵的行
  	private int width; 					//矩阵的列

  	private void init(int m,int n)		//元素随机赋值方法
  	{
    		table=new int[m][n];			//分配矩阵元素数组内存空间
    		for(int i=0; i<m; i++)
      		for(int j=0; j<n; j++)
      		{
        			table[i][j]=(int)(Math.random() * 100); //元素随机赋值
      		}
 	}

  	public MyMatrix(int n)				//构造方法，构造方阵
  	{
      	height = n;						
      	width = n;
      	this.init(height,width);		//调用元素随机赋值方法
  	}

  	public MyMatrix(int m,int n) 		//构造方法，构造m行n列矩阵
  	{
    		height=m;
    		width=n;
    		this.init(height,width); 		//调用元素随机赋值方法
  	}

  	public int getHeight()				//返回矩阵的行数方法
  	{
    		return height;
  	}

  	public int getWidth()				//返回矩阵的列数方法
  	{
    		return width;
  	}

  	public int[][] getTable()			//返回矩阵方法
  	{
    		return table;
  	}

  	public MyMatrix add(MyMatrix b)		//矩阵加方法
    {    	 
if(this.getHeight()!=b.getHeight()&&
this.getWidth()!=b.getWidth())
    		{
      		System.out.println("the two matrix don't macth");
      		return null;
    		}
    		MyMatrix result=new MyMatrix(b.getHeight(),b.getWidth());
    		for(int i=0;i<b.getHeight();i++)
      		for(int j=0;j<b.getWidth();j++)
      		{
        			result.table[i][j]=this.table[i][j]+b.table[i][j];
      		}
    		return result;
  	}

  	public MyMatrix subtract(MyMatrix b) 			//矩阵减方法
  	{
    		if(this.getHeight()!=b.getHeight()&&
this.getWidth()!=b.getWidth())
    		{
      		System.out.println("the two matrix don't macth");
      		return null;
    		}

    		MyMatrix result=new MyMatrix(b.getHeight(),b.getWidth());
    		for(int i=0;i<b.getHeight();i++)
      		for(int j=0;j<b.getWidth();j++)
      		{
        			result.table[i][j]=this.table[i][j]-b.table[i][j];
      		}
    		return result;
  	}
}

// TestMyMatrix.java文件
public class TestMyMatrix 							//测试类
{
  	public static void main(String[] args) 
  	{
   		MyMatrix mm1=new MyMatrix(4,4);
   		MyMatrix mm2=new MyMatrix(4,4);
   		MyMatrix mm3=new MyMatrix(4,5);
   		MyMatrix mm4=new MyMatrix(4,5);

   		MyMatrix add_result=mm1.add(mm2);
   		int[][] add_table=add_result.getTable();
   		MyMatrix subtract_result=mm3.subtract(mm4);
   		int[][] subtract_table=subtract_result.getTable();

   		System.out.println("two matrix add result：");
   		for(int i=0;i<add_result.getHeight();i++)
   		{
     		for(int j=0;j<add_result.getWidth();j++)
     		{
       			System.out.print(add_table[i][j]+"  ");
     		}
     		System.out.println();
   		}

   		System.out.println("two matrix subtract result：");
  		for(int i=0;i<subtract_result.getHeight();i++)
  		{
    			for(int j=0;j<subtract_result.getWidth();j++)
    			{
      			System.out.print(subtract_table[i][j]+"  ");
    			}
    			System.out.println();
  		}
  	}
}